Do you know what your teen athlete is taking? A quick guide to some of the most common drugs and supplements

The term "sports enhancement supplements" means different things to different people. To some, sports enhancement supplements could mean a protein shake with an extra vitamin boost. To others, it could mean an illegal anabolic steroid.

Although the Dietary Supplement Health and Education Act of 1994 governs supplements, the FDA views products as safe until they are proven harmful. With little hard data, the side effects and long-term consequences of supplement use by teenagers are not yet known.

Here's a list of the sports enhancement supplements studied by Alison Field, ScD, assistant professor of pediatrics at Children's Hospital, Boston, and Harvard Medical School, and her colleagues. Learn what each is intended to do, keeping in mind that because products are not regulated, the powders, bars, or pills may not contain the ingredients printed on the package.

Protein Powders and Shakes These products are generally taken as nutritional supplements or meal replacements with an eye to boosting energy. Upping your protein intake can help muscles rebuild themselves after hard workouts, and may help your athlete recover after a tough practice. If your child has other health concerns or if you're worried he or she may be overdoing it, speak with your pediatrician to get advice on the best balanced diet.

Creatine Creatine is a natural substance found in our muscles. As a supplement, it's widely sold in powder or caplet form at sports nutrition stores for the purpose of increasing muscle mass and therefore enhancing performance. But don't let its ubiquity convince you all supplements are perfectly legit: Consumer Lab tested various creatine products and found that only half of them passed its test standard.

Amino Acids/Hydroxymethylbutyrate (HMB) Amino acids are the building blocks of protein in the body. HMB, a metabolite of the amino acid leucine, is used to boost body strength. Like creatine, you'll find it in supplement form in nutrition stores, but studies haven't proven its effectiveness and the contents of different supplements may vary.

Dehydroepiandrosterone (DHEA) DHEA is a steroid produced in the adrenal glands and converted into sex hormones. The effects of DHEA are similar to testosterone. As with other steroids, side effects may include shrinking of the testicles in men and disruption of the menstrual cycle in women, behavioral changes and aggressiveness, among others. DHEA is not illegal to sell in the U.S., but has been banned as a performance-enhancing drug by the NBA, NFL, NCAA and other sports organizations worldwide.

Human Growth Hormone (HGH) Growth hormone, or somatotropin, is necessary for growth. It's used by body builders to strengthen and build muscle, and burn fat. HGH can be prescribed for children with a growth deficiency and for other medical reasons, but it's also gained popularity in recent years as an anti-aging supplement—an unapproved and unproven usage that most doctors advise against.

Anabolic Steroids A controlled substance, an anabolic steroid is a synthetic version of testosterone that can be injected, taken orally, or used transdermally. The drugs are used to increase muscle weight, and are banned by major sporting organizations around the world. Side effects in males include shrinking of the testicles and breast development. In females, side effects include facial hair growth, menstrual changes, deepened voice, and acne. In teenagers, growth may be halted prematurely and permanently.